Method for producing a color filter

ABSTRACT

A color filter including: a transparent substrate; a light shielding part formed on the transparent substrate and contains at least a light shielding material and a resin; and a colored layer formed in the opening part of the light shielding part on the transparent substrate to cover a part of the light shielding part. The light shielding part has: the width of the thick film region, 85% of more of the maximum film thickness of the light shielding part and disposed in the central part of the light shielding part, in a range of 30% to 60% of the light shielding part line width; and the width of each of the thin film regions, 50% or less of the maximum film thickness of the light shielding part and disposed on the both side parts of the light shielding part, in a range of 10% to 20% of the light shielding part line width.

TECHNICAL FIELD

The present invention relates to a high quality color filter with littlerisk of disturbing the liquid crystal alignment, or the like at the timeof being used for a liquid crystal display apparatus.

BACKGROUND ART

At the time of forming a color filter used for a liquid crystal displayapparatus, in general, a method of forming a light shielding part on atransparent substrate for forming a color filter, and forming a coloredlayer in the opening part thereof, or the like is used. As such a lightshielding part, conventionally, a metal thin film with a metal such as achromium vacuum deposited and processed by etching has been used.Recently, however, development of a resin-made light shielding partformed by coating a resin with a black pigment, or the like dispersedand patterning by the photolithography method, or the like has beenpromoted so as to realize its practical use. According to such aresin-made light shielding part, as compared with a light shielding partcomprising a metal thin film, the process of the vacuum deposition orthe like can be eliminated so as to be used for a large area colorfilter, and thus it is advantageous.

However, as compared with the light shielding part comprising a metalthin film of such as a chromium, for obtaining a sufficient opticaldensity, the film thickness should be large. Therefore, the filmthickness of the colored layer formed to cover a part of the resin-madematrix for the purpose of preventing the void, or the like is madelarger. As a result, the difference in the film thickness between theregion with the light shielding part and the colored layer laminated,and the region with only the colored layer formed becomes larger.

In particular, in the case where the colored layers of such as red (R),green (G), blue (B) are formed by a plurality of times on a transparentsubstrate with the light shielding part formed, the difference in thefilm thickness between the region with the light shielding part and thecolored layer laminated, and the region with only the colored layerformed becomes larger. The method for forming the colored layer of sucha color filter will be explained with reference to, for example, FIGS.4A to 4E. First, the colored layer 3R of a first color is formed on theopening part of the transparent substrate 1 with the light shieldingpart 2 formed so as to cover a part of the light shielding part 2 by thephotolithography method, or the like (FIG. 4A). Subsequently, by coatinga colored layer forming composition 4B for forming the colored layer ofa second color onto the transparent substrate 1 with the colored layer3R formed (FIG. 4B), and curing only the purposed region, a coloredlayer 3B is formed (FIG. 4C). Here, at the time of coating theabove-mentioned colored layer forming composition 4B, the colored layer3R is formed on the transparent substrate 1 so that the film thicknessof the colored layer forming composition 4B coated thereon becomeslarger in the vicinity of the region with the colored layer 3R formed.Therefore, the film thickness on the colored layer 3R side of thecolored layer 3B to be formed by curing the colored layer formingcomposition 4B becomes higher than the film thickness of the coloredlayer 3R. In the same manner, in the case of applying a colored layerforming composition 4G to be formed for the third color (FIG. 4D), sincethe colored layers 3R, and 3G are already formed on the both sides ofthe region for forming the colored layer, the film thickness of thecolored layer forming composition 4G becomes higher in the vicinitythereof so that at the time of providing the colored layer 3G by curing,or the like, as compared with the colored layers 3R and 3B, the filmthickness in the region laminated with the light shielding part 2becomes higher (FIG. 4E).

In the case where the color filter has a difference in a film thicknessbetween the region with the light shielding part and the colored layerlaminated and the region with only the colored layer formed accordingly,the problems such as a disturbance of the alignment of the liquidcrystal in the liquid crystal layer formed on the color filter so as togenerate the light leakage, or breakage of the ITO film formed on thecolor filter have been generated. Furthermore, the problem such ascausing unevenness of the gap at the time of disposing the color filterand the counter substrate to face to each other has been involved.

Moreover, in the case of a color filter having a stripe-shaped coloredlayer, for example, as shown in FIG. 5A, the colored layer 3 is formedin a stripe form on the transparent substrate with the light shieldingpart 2 formed. Here, the light shielding part 2 is formed orthogonallywith the colored layer 3 in the a direction. For example, as shown inthe cross sectional view in the b direction (FIG. 5B) of FIG. 5A, in theportion with the light shielding part 2 orthogonal to the colored layer3, the light shielding part 2 is totally covered with the colored layer3. At the time, as mentioned above, in the case where the film thicknessof the resin-made light shielding part 2 is large, the difference in thefilm thickness between the region with the light shielding part 2 andthe colored layer 3 laminated, and the region with only the coloredlayer 3 formed becomes larger. Moreover, since the difference in thefilm thickness continues like a line in the a direction, it may become acause of further disturbing the liquid crystal alignment or a cause ofgenerating the breakage of the ITO film.

DISCLOSURE OF THE INVENTION Problem to be Solved by the Invention

From the above-mentioned, a high quality color filter with littledifference in the thickness between the film thickness of the regionwith the resin-made light shielding part and the colored layersuperimposed, and the film thickness of the region with only the coloredlayer formed, and with little liquid crystal alignment disturbance, orthe like has been desired to be provided.

Means for Solving the Problem

The present invention provides a color filter comprising: a transparentsubstrate, a light shielding part formed on the transparent substrateand contains at least a light shielding material and a resin; and acolored layer formed in the opening part of the light shielding part onthe transparent substrate to cover a part of the light shielding part,characterized in that the light shielding part has: the width of thethick film region, 85% of more of the maximum film thickness of theabove-mentioned light shielding part and disposed in the central part ofthe light shielding part, in a range of 30% to 60% of the lightshielding part line width; and the width of each of the thin filmregions, 50% or less of the maximum film thickness of the lightshielding part and disposed on the both side parts of the lightshielding part, in a range of 10% to 20% of the light shielding partline width.

According to the present invention, since the width of theabove-mentioned thick film region disposed in the central part of thelight shielding part is in the above-mentioned range, and the width ofthe above-mentioned thin film region disposed in the both side parts ofthe light shielding part is in the above-mentioned range, the filmthickness in the central part of the light shielding part can be maderelatively small so as to have a light shielding part with a gentlysloping shape, or the like. Thereby, for example, at the time of coatinga colored layer forming composition for forming a colored layer onalight shielding part, or the like, the coating amount of the coloredlayer forming composition to be applied on the central part of the lightshielding part can be made less so that the film thickness in theportion with the colored layer and the light shielding part laminatedcan be provided smaller. Moreover, for example, in the case where thecolor filter of the present invention is a color filter having a stripetype colored layer, also in the portion with the stripe type coloredlayer and the light shielding part provided orthogonally so that thestripe type colored layer and the light shielding part are laminated,the film thickness of the stripe type colored layer formed on the thickfilm region of the light shielding part can be provided thinly so thatthe difference of the film thickness with respect to the region withonly the stripe type colored layer formed can be made smaller. Thereby,at the time of using the color filter for the liquid crystal displayapparatus, occurrence of such as a disturbance of the alignment of theliquid crystal layer formed on the color filter, breakage of the ITOfilm or unevenness of the gap with respect to the oppositely facingsubstrate can be made smaller. Moreover, also in the case where acolored layer is formed in a bent pattern in a color filter for IPS (InPlane Switching)-mode, the same can be applied.

In the above-mentioned invention, it is preferable that the differencebetween the maximum film thickness of the stacked part with the coloredlayer superimposed on a part of the light shielding part and the filmthickness of the central part of the colored layer formed in the openingpart of the light shielding part is 0.5 μm or less. Thereby, occurrenceof such as an irregularity of the alignment of the liquid crystal layerformed on the color filter of the present invention or breakage of theITO film can further be reduced.

Further, the present invention provides a color filter comprising: atransparent substrate; a light shielding part formed on the transparentsubstrate and contains at least a light shielding material and a resin;a colored layer formed in the opening part of the light shielding parton the transparent substrate to cover a part of the light shieldingpart; and a crossing part with the colored layer and the light shieldingpart crossing each other such that the colored layer covers the lightshielding part, characterized in that the difference between the maximumfilm thickness of the crossing part and the film thickness of thecentral part of the colored layer formed in the opening part of thelight shielding part is 0.5 μm or less.

According to the present invention, for example, in a stripe type colorfilter or a color filter with a colored layer formed in a bent patternhaving the above-mentioned crossing part has the difference between theabove-mentioned crossing part and the film thickness of the coloredlayer in the above-mentioned range. As a result, occurrence of such asan irregularity of the alignment of the liquid crystal layer formed onthe color filter of the present invention or unevenness of the gap withrespect to the oppositely facing substrate can be reduced.

Effect of the Invention

According to the present invention, the film thickness of the portionwith the colored layer and the light shielding part superimposed can bemade lower. Moreover, in the case where a color filter of the presentinvention is, for example, a color filter having a stripe type coloredlayer, also concerning the portion with the stripe type colored layerand the light shielding part laminated, wherein with the stripe typecolored layer and the light shielding part provided orthogonally, thefilm thickness of the stripe type colored layer formed on the thick filmregion of the light shielding part can be made smaller. Thereby, at thetime of using a color filter of the present invention for a liquidcrystal display apparatus, occurrence of such as a disturbance of thealignment of the liquid crystal layer formed on the color filter,breakage of the ITO film, unevenness of the gap with respect to theoppositely facing substrate can be reduced.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1A and 1B are explanatory diagrams for explaining a color filterof the present invention.

FIG. 2 is an explanatory diagram for explaining a light shielding partused in the present invention.

FIG. 3 is an explanatory diagram for explaining a light shielding partused in the present invention.

FIGS. 4A to 4E is a process diagram for explaining an example of amethod for forming a colored layer of a common color filter.

FIGS. 5A and 5B are explanatory diagrams for explaining a color filterhaving a common stripe type colored layer.

FIG. 6 is an explanatory diagram for explaining a colored layer formedin a bent pattern in a color filter for IPS (In Plane Switching)-mode.

EXPLANATION OF REFERENCES

-   1 . . . Transparent substrate-   2 . . . Light shielding part-   3 . . . Colored layer-   4 . . . Stacked part-   5 . . . Orthogonally stacked part

BEST MODE FOR CARRYING OUT THE INVENTION

The present invention relates to a high quality color filter with littlerisk of disturbing the liquid crystal alignment, or the like at the timeof being used for a liquid crystal display apparatus, and it includestwo embodiments.

Hereinafter, each embodiment will be explained in detail.

1. First Embodiment

First, a first embodiment of the color filter of the present inventionwill be explained. The first embodiment of the color filter of thepresent invention is a color filter comprising: a transparent substrate;a light shielding part formed on the transparent substrate and containsat least a light shielding material and a resin; and a colored layerformed in the opening part of the light shielding part on thetransparent substrate to cover a part of the light shielding part,characterized in that the width of the thick film region, 85% of more ofthe maximum film thickness of the light shielding part and disposed inthe central part of the light shielding part, is in a predeterminedrange with respect to the light shielding part line width, and the widthof each of the thin film regions, 50% or less of the maximum filmthickness of the light shielding part and disposed on the both sideparts of the light shielding part, is in a predetermined range withrespect to the light shielding part line width.

For example, as shown in FIG. 1A, the color filter of this embodiment isa color filter comprising a transparent substrate 1, a light shieldingpart 2 formed on the transparent substrate 1, and a colored layer 3 (3R,3G and 3B) formed to cover the light shielding part 2 partially,wherein, for example, as shown in FIG. 1B, the light shielding part 2has the width m of a thick film region having a film thickness of apredetermined ratio or more with respect to the maximum film thickness tof the light shielding part in a predetermined range with respect to thelight shielding part line width n in the central part of the lightshielding part 2, and the width y of a thin film region having a filmthickness of a predetermined ratio or less with respect to the maximumfilm thickness t of the light shielding part is each in a predeterminedrange with respect to the light shielding part line width n in the bothside parts of the light shielding part 2. The light shielding part linewidth denotes the width from the end part to the other end part of thelight shielding part.

Moreover, the above-mentioned side parts denote the region including theend part of the light shielding part, and the central part denotes theregion including the maximum film thickness part of the light shieldingpart. The shape of the above-mentioned light shielding part denotes thelight shielding part shape in the effective display area of the colorfilter.

Here, in the case where a color filter is formed using a resin-madelight shielding part having a common shape, as mentioned above, sincethe film thickness of the light shielding part is large in the portionwith the colored layer and the light shielding part superimposed, thecolored layer is formed in a hogged form so as to generate thedifference in the film thickness with respect to the region with onlythe colored layer formed and to have a step. Thereby, in the case wherethe color filter is used for a liquid crystal display apparatus, thelight leakage may be generated due to the disturbance of the liquidcrystal alignment in the liquid crystal layer to be disposed onto thestep, or the ITO film may be broken by the step, or the like. Moreover,for example, in the case of keeping the gap between the color filter andthe oppositely facing substrate using a bead-shaped spacer, a problem isinvolved in such as that the gap between the oppositely facing substrateand the color filter cannot be constant due to the step.

On the other hand, according to this embodiment, a shape with the widthof the above-mentioned thick film region in the central part of thelight shielding part provided relatively narrowly and the width of theabove-mentioned thin film regions in the both end parts providedrelatively widely can be provided. Thereby, for example, in the casewhere a colored layer is formed on the light shielding part, the filmthickness with the colored layer and the light shielding part laminatedcan be made relatively small so that the difference with respect to thefilm thickness of the colored layer formed in the opening part of thelight shielding part can be made smaller. Therefore, at the time ofusing the color filter of this embodiment for a liquid crystal displayapparatus, a high quality color filter capable of constantly keeping thegap between the oppositely facing substrate and the color filter withlittle influence on such as the alignment property of the liquid crystallayer formed on the color filter or the ITO film can be provided.

Here, the above-mentioned thick film region is a region in the centralpart of the light shielding part with 85% or more or the maximum filmthickness of the light shielding part, and the above-mentioned thin filmregion is a region in the both end parts of the light shielding partwith 50% or less of the maximum film thickness of the light shieldingpart. The maximum film thickness of the light shielding part denotes thefilm thickness of the portion where the film thickness in each lightshielding part is largest.

In this embodiment, it is preferable that the thick film region width isin a range of 30% to 60% of the light shielding part line width, inparticular, in a range of 30% to 50%. Moreover, it is preferable thatthe above-mentioned width of the thin film region, that is, the distancefrom the end part of the light shielding part to the portion with the50% film thickness of the maximum film thickness of the light shieldingpart is in a range of 10% to 20% of the light shielding part line widthat the both side parts. Thereby, even in the case of forming the coloredlayer on the light shielding part, the difference in the film thicknessbetween the region with only the colored layer formed and the regionwith the colored layer covering the light shielding part can be madesmaller.

As to the measurement of the width of the above-mentioned thick filmregion or thin film region can be calculated by, for example, the crosssectional shape of the central part of the light shielding partphotographed with a scanning electron microscope (SEM), or the like.

Moreover, here, in this embodiment, for example, as shown in FIG. 2, itis preferable that the difference between the maximum film thickness rof the stacked part 4 with the colored layer 3 superimposed on a part ofthe light shielding part 2 and the film thickness s of the central partof the colored layer 3 formed in the opening part of the light shieldingpart 2 is 0.5 μm or less, preferably 0.4 μm or less, and particularlypreferably 0.3 μm or less. According to the range, disturbance of thealignment of the liquid crystal on the stacked part, breakage of the ITOfilm, or the like can be more effectively prevented, and moreover, thegap of the liquid crystal display apparatus can be made constant. Theabove-mentioned stacked part denotes the region with the light shieldingpart and the colored layer laminated. Further, the film thickness of thecentral part of the colored layer denotes the film thickness of, forexample, the colored layer at the crossing of the diagonals of therectangle in the case where the shape of the opening part of the lightshielding part is a rectangle. Here, as mentioned above, in the casewhere the colored layer is formed separately by a plurality of times, itis preferable that the difference between the film thickness of the allstacked parts and the film thickness of the central part of the coloredlayer is in the above-mentioned range.

Hereinafter, the color filter of this embodiment will be explained indetail for each configuration.

(Light Shielding Part)

First, the light shielding part used in this embodiment will beexplained. The light shielding part used in this embodiment is to beformed on the transparent substrate to be described later, and itcontains at least a light shielding material and a resin so as to beused as the light shielding part of a color filter.

The shape of the light shielding part in this embodiment is notparticularly limited as long as it is a shape to have the width of theabove-mentioned thick film region and the above-mentioned thin filmregion in a predetermined range, and it can be formed particularlypreferably in a hogged form. Thereby, the film thickness of the coloredlayer formed on the thick film region of the light shielding part can bemade smaller.

Moreover, the width of the light shielding part entirety used in thisembodiment, that is, the light shielding part line width is, although italso depends on the shape of the color filter, or other factors, ingeneral in a range of 6 μM to 35 μm, preferably 10 μm to 30 μm, andparticularly preferably 16 μm to 30 μm. In the case where the colorfilter of this embodiment is used for the mobile application, it ispreferable that the above-mentioned light shielding part line width isin a range of 6 μm to 15 μm. Moreover, although the height can also beselected optionally, it is in general 0.5 μm to 2.5 μm, preferably 0.8μm to 2.5 μm, and particularly preferably about 0.8 μm to 1.5 μm.

In this embodiment, the colored layer to be described later is formed tocover a part of the light shielding part. The width of the lightshielding part to be covered with the colored layer is in general about2 μm to 10 μm from the end part of the light shielding part, and it ispreferably about 2 μm to 6 μm. Thereby, a high quality color filterwithout a void, or the like can be provided.

Here, the material, or the like of the above-mentioned light shieldingpart is not particularly limited as long as at least the light shieldingmaterial and the resin are contained. In general, the light shieldingpart can be formed with a light shielding part forming composition witha photo initiator, a monomer, or the like added to the light shieldingmaterial and the resin.

As the above-mentioned light shielding material, a material used for aresin-made light shielding part to be used in general for a color filtercan be used. For example, carbon fine particles, light shieldingparticles of such as a metal oxide, an inorganic pigment or an organicpigment can be presented.

As the resin to be contained in the light shielding part used in thepresent embodiment, the following examples can be cited: anethylene-vinyl acetate copolymer, an ethylene-vinyl chloride copolymer,an ethylene-vinyl copolymer, a polystyrene, an acrylonitrile-styrenecopolymer, a ABS resin, a polymethacrylic acid resin, anethylene-methacrylic acid resin, a polyvinyl chloride resin, achlorinated vinyl chloride, a polyvinyl alcohol, a cellulose acetatepropionate, a cellulose acetate butylate, a nylon 6, a nylon 66, a nylon12, a polyethylene terephthalate, a polybutylene terephthalate, apolycarbonate, a polyvinyl acetal, a polyether ether ketone, a polyethersulfone, a polyphenylene sulfide, a polyallylate, a polyvinyl butylal,an epoxy resin, a phenoxy resin, a polyimide resin, a polyamide imideresin, a polyamic acid resin, a polyether imide resin, a phenol resin, aurea resin.

Furthermore, a polymer or a copolymer comprising one or more kindsselected from the group consisting of a methyl (meth)acrylate, an ethyl(meth)acrylate, a n-propyl (meth)acrylate, an isopropyl (meth)acrylate,a sec-butyl (meth)acrylate, an isobutyl (meth)acrylate, a tert-butyl(meth)acrylate, a n-pentyl (meth)acrylate, a n-hexyl (meth)acrylate, a2-ethyl hexyl (meth)acrylate, a n-octyl (meth)acrylate, a n-decyl(meth)acrylate, a styrene, an α-methyl styrene, a N-vinyl-2-pyrolidoneas a polymerizable monomer and a glycidyl (meth)acrylate, and one ormore kinds selected from the group consisting of a dimer of a(meth)acrylic acid and an acrylic acid (such as M-5600 manufactured byTOA GOSEI CO., LTD.), an itaconic acid, a crotonic acid, a maleic acid,a fumaric acid, a vinyl acetate and an anhydride thereof can also bepresented. Moreover, a polymer produced by adding an ethylenicallyunsaturated compound having a glycidyl group or a hydroxyl group to thecopolymer, or the like can also be presented, but it is not limitedthereto.

Among the examples, since a polymer containing an ethylenicallyunsaturated bond forms a cross linking bond with a monomer so as toobtain the excellent strength, it can be used particularly preferably.

As the monomer which can be used to form the light shielding part usedin the present embodiment, polyfunctional acrylate monomers can be citedas an example, and a compound having two or more ethylenic unsaturatedbonds containing group such as an acrylic group and a methacrylic groupcan be used. Specifically, an ethylene glycol (meth)acrylate, adiethylene glycol di(meth)acrylate, a propylene glycol di(meth)acrylate,a dipropylene glycol di(meth)acrylate, a polyethylene glycoldi(meth)acrylate, a polypropylene glycol di(meth)acrylate, a hexanedi(meth)acrylate, a neopenthyl glycol di(meth)acrylate, a glycerindi(meth)acrylate, a glycerin tri(meth)acrylate, a trimethylol propanetri(meth)acrylate, a 1,4-butane diol diacrylate, pentaerythritol(meth)acrylate, a pentaerythritol tri(meth)acrylate, a pentaerythritoltetra(meth)acrylate, a dipentaerythritol hexa(meth)acrylate, adipentaerythritol penta(meth)acrylate or the like can be presented as anexample.

The polyfunctional acrylate monomers may be used as a combination of twoor more kinds. In this embodiment, a (meth) acrylic denotes either of anacryl or a methacryl, and a (meth)acrylate denotes either of an acrylategroup or a methacrylate.

As the photo initiator which can be used in the present embodiment, aphoto radical polymerization initiating agent to be activated by aultraviolet ray, an ionizing radiation, a visible light, or an energyline of the other wavelengths, in particular, 365 nm or less can beused. As such a photo polymerization initiating agent, specifically, abenzophenone, an o-benzoyl methyl benzoate, a 4,4-bis(dimethyl amine)benzophenone, a 4,4-bis(diethyl amine) benzophenone, anα-amino-acetophenone, a 4,4-dichlorobenzophenone, a 4-benzoyl-4-methyldiphenyl ketone, a dibenzyl ketone, a fluolenone, a 2,2-diethoxyacetophenone, a 2,2-dimethoxy-2-phenyl acetophenone, a2-hydroxy-2-methyl propiophenone, a p-tert-butyl dichloroacetophenone, athioxantone, a 2-methyl thioxantone, a 2-chlorothioxantone, a2-isopropyl thioxantone, a diethyl thioxantone, a benzyl dimethyl ketal,a benzyl methoxy ethyl acetal, a benzoin methyl ether, a benzoin butylether, an anthraquinone, a 2-tert-butyl anthraquinone, a 2-amylanthraquinone, a β-chloranthraquinone, an anthrone, a benzanthrone, adibenzsuberone, a methylene anthrone, a 4-adidobenzyl acetophenone, a2,6-bis(p-adidobendilidene)cyclohexane, a2,6-bis(p-adidobendilidene)-4-methyl cyclohexanone, a2-phenyl-1,2-butadion-2-(o-methoxy carbonyl) oxime, a 1-phenyl-propanedion-2-(o-ethoxy carbonyl) oxime, a 1,3-diphenyl-propanetrion-2-(o-ethoxy carbonyl) oxime, a 1-phenyl 3-ethoxy-propanetrion-2-(o-benzoyl) oxime, a Michler's ketone, a 2-methyl-1[4-(methylthio) phenyl]-2-morpholino propane-1-on, a 2-benzyl-2-dimethylamino-1-(4-morpholino phenyl)-butanone, a naphthalene sulfonyl chloride,a quinoline sulfonyl chloride, a n-phenyl thioacrydone, a 4,4-azo bisisobuthylonitrile, a diphenyl disulfide, a benzthiazol disulfide, atriphenyl phosphine, a camphor quinone, N1717 manufactured by AsahiDenka Co., Ltd. a carbon tetrabromate, a tribromo phenyl sulfone, abenzoin peroxide, an eosin, a combination of a photo reducing pigmentsuch as a methylene blue and a reducing agent such as an ascorbic acidand a triethanol amine, or the like can be presented as an example. Inthis embodiment, these photo polymerization-initiating agents can beused alone or as a combination of two or more kinds.

Here, in this embodiment, as a method for forming a light shielding partto have the above-mentioned shape, a method of providing thethermoplasticity to the light shielding part forming composition, or thelike by such as using a low molecular material out of theabove-mentioned resins as the resin to be contained in the lightshielding part forming composition, or adding a large amount of theabove-mentioned monomer can be presented. In this case, by forming arectangular light shielding part and subsequently applying the heat tothe light shielding part by the same method as for the common lightshielding part in the region to form the light shielding part, the lightshielding part forming composition can be softened so as to provide theabove-mentioned shape.

Moreover, for example, a method of using a surface curing photoinitiator by a large amount out of the above-mentioned photo initiatorsas the photo initiator to be contained in the above-mentioned resincomposition can be presented. In this case, for example, at the time ofexecuting etching by such as a photolithography method, since thephotosetting does not proceed completely in the inside of the lightshielding part even though the surface of the region to have the lightshielding part formed is cured, it is etched in an inverse tapered shapewith a high angle. Therefore, after finishing the etching operation, bypost baking the inversely tapered light shielding part, the taperedportion is lowered so that the light shielding part having theabove-mentioned shape can be formed.

Furthermore, a method of pouring the above-mentioned light shieldingpart forming composition into a mold having a shape for forming thelight shielding part to cure, and attaching the light shielding partonto a transparent substrate, or the like can also be used. Moreover, byutilizing a half tone mask and changing the exposing amount, a lightshielding part having the above-mentioned shape can also be formed.

(Colored Layer)

Next, the colored layer used in this embodiment will be explained. Theshape or the like of the colored layer used in this embodiment is notparticularly limited as long as it is formed in the opening part of theabove-mentioned light shielding part so as to cover a part of the lightshielding part as mentioned above. For example, three colored layerforming compositions of red (R), green (B) and blue (B) can be used in aknown arrangement such as the stripe type, the mosaic type, the triangletype, and the four pixel arrangement type, with the coloring area setoptionally. The above-mentioned opening part denotes a region withoutformation of the light shielding part on the transparent substrate.

In this embodiment, a stripe type colored layer is particularlypreferable, as it will be explained in the second embodiment to bedescribed later. Thereby, the advantages of this embodiment can beutilized also in a region with the colored layer and the light shieldingpart provided orthogonally.

Here, the film thickness of the colored layer formed in this embodimentcan be selected optionally according to the targeted color filter. It isin general about 1.0 μm to 3.0 μm, and more preferably about 1.2 μm to2.5 μm. Thereby, the difference of the film thickness between the regionformed in the opening part of the light shielding part and the regionformed on the light shielding part can be made smaller.

The formation method of the colored layer used in this embodiment can bea method used at the time of producing a common color filter such as thephotolithography method and the ink jet method. Moreover, since thematerial of the colored layer used in this embodiment can be same as acolored layer used for a common color filter, detailed explanation isomitted here.

(Transparent Substrate)

Next, the transparent substrate used in this embodiment will beexplained. The transparent substrate used in this embodiment is notparticularly limited as long as it can be generally used for a colorfilter. A transparent rigid material without flexibility such as aquartz glass, a Pyrex (registered trademark) glass and a syntheticquartz plate, or a transparent flexible material having the flexibilitysuch as a transparent resin film and an optical resin plate can be used.

(Color Filter)

The color filter in this embodiment is not particularly limited as longas the above-mentioned light shielding part and the above-mentionedcolored layer are formed on the above-mentioned transparent substrate.For example, as needed, a protection layer, an electrode layer, or thelike may be formed.

2. Second Embodiment

Next, a second embodiment of the color filter of the present inventionwill be explained. The second embodiment of the color filter of thepresent invention is a color filter comprising: a transparent substrate;a light shielding part formed on the transparent substrate and containsat least a light shielding material and a resin; a colored layer formedin the opening part of the light shielding part on the transparentsubstrate to cover a part of the light shielding part; and a crossingpart with the colored layer and the light shielding part crossing eachother such that the colored layer covers the light shielding part,characterized in that the difference between the maximum film thicknessof the crossing part and the film thickness of the central part of thecolored layer formed in the opening part of the light shielding part isin a predetermined range.

The above-mentioned crossing part denotes a region with the coloredlayer and the light shielding part laminated in a region with thecolored layer and the light shielding part crossing each other. As acolor filter having such a crossing part, for example, a color filterhaving a stripe type colored layer 3, as shown in FIG. 5A can bepresented. According to a color filter having a stripe type coloredlayer, since the light shielding part 2 is formed also in the adirection of FIG. 5A, for example, as shown in FIG. 5B, a portion withthe light shielding part 2 and the colored layer 3 crossing each othercovered with the colored layer 3.

Moreover, as a color filter having a crossing portion with the coloredlayer crossing the light shielding part to cover the same, for example,as shown in FIG. 6, the case of forming the colored layer 3 in a bentpattern in a color filter for IPS (In Plane Switching)-mode can bepresented. According to a color filter for IPS (In PlaneSwitching)-mode, for example, as it is disclosed in the official gazetteof the Japanese Patent Application Laid Open (JP-A) No. 9-311334, acolored layer formed in a bent pattern is used commonly in terms of theviewing angle, or the like. According also to such a color filter, as inthe case of the above-mentioned stripe type colored layer, the lightshielding part is formed by crossing the colored layer for sectioningthe colored layer.

Here, in this embodiment, the difference between the maximum filmthickness of the crossing part and the film thickness in the centralpart of the colored layer formed in the opening part of the lightshielding part is in a predetermined range. For example, as shown in thecross sectional view in the b direction (FIG. 3) of FIG. 5A, thedifference between the maximum film thickness e of the light shieldingpart 2 formed on the transparent substrate 1 and the colored layer 3formed to cover the entirety of the light shielding part 2 and the filmthickness f of the central part in the stripe type colored layer 3formed in the opening part of the light shielding part 2 is formed in apredetermined range. Thereby, at the time of using the color filter ofthis embodiment in a liquid crystal display apparatus, the problems suchas an occurrence of disturbance of the alignment of the liquid crystalformed on the color filter, breakage of the ITO film formed on the colorfilter, or unevenness of the gap between the oppositely facing substrateand the color filter can be reduced.

The difference of the film thickness between the crossing part and thecolored layer central part is specifically, in a range of 0.5 μm orless, preferably 0.1 μm to 0.4 μm, and particularly preferably 0.1 μm to0.2 μm. The maximum film thickness of the crossing part denotes the filmthickness of a portion with the film thickness of the light shieldingpart and the colored layer in the crossing part provided maximally.

Here, in this embodiment, the forming method, the forming material, orthe like of the color filter are not particularly limited as long as thedifference in the film thickness of the crossing part and of the centralpart of the colored layer can be in the above-mentioned range. It isparticularly preferable to use the light shielding part of the colorfilter explained in the above-mentioned “1. First embodiment” since theabove-mentioned difference of the film thickness can be realized.

Since the light shielding part, the colored layer, the transparentsubstrate, or the like used in this embodiment can be same as those inthe above-mentioned “1. First embodiment”, detailed explanation isomitted here. Moreover, for the color filter of this embodiment, asneeded, other members may also be provided.

The present invention is not limited to the above-mentioned embodiments.The above-mentioned embodiments are examples and any one substantiallyhaving the same configuration as the technological idea disclosed in theclaims of the present invention so as to achieve the same effects isincluded in the technological scope of the present invention.

EXAMPLES

Hereinafter, with reference to the example and the comparative example,the present invention will be explained further specifically.

Example

As the substrate for a color filter substrate, a 0.7 mm thickness glasssubstrate (produced by Coning Inc., 1737 glass) was prepared. Afterwashing the substrate by an ordinary method, a photosensitive resincomposition for a black matrix having the following composition wascoated on one entirety side of the substrate, and heated on a hot plateafter drying. Thereafter, after the exposure via a predetermined photomask, it was developed excessively and baked so as to form a blackmatrix (line width: 14.4 μm, thickness 1.1 μm). The thick film region atthe time was 5.8 μm, and the thin film region was 2.4 μm.

(Composition for a Black Matrix) Carbon black 61 parts by weight

Photosensitive resin composition 39 parts by weight

Methoxy butyl acetate 300 parts by weight

The above-mentioned photosensitive resin composition has theunder-mentioned composition. The same is applied to the photosensitiveresin composition to be used in the following example.

(Photosensitive Resin Composition)

Acrylic resin 32 parts by weight

Dipentaerythritol hexaacrylate 42 parts by weight

Epicoat 180S70 (produced by Mitsubishi Yuka Shell Corp.) 18 parts byweight

Irg. 907 (produced by Ciba Specialty Chemicals,) 8 parts by weight

Next, each coating solution for a red pattern, a green pattern and ablue pattern of the under-mentioned composition was prepared, and usingthem, a red pattern, a green pattern and a blue pattern (each thickness1.7 μm) were respectively formed in a pixel region according to a knownpigment dispersion method to provide a color filter. The differencebetween the maximum film thickness in the stacked part with the coloredlayer superimposed on a part of the light shielding part of the formedcolor filter and the film thickness of the central part of the coloredlayer formed in the opening part of the light shielding part was 0.3 μm.

(Composition of a Coating Solution for a Red Pattern)

PR254 dispersion 33 parts by weight

Photosensitive resin composition 67 parts by weight

Propylene glycol monomethyl ether acetate 400 parts by weight

(Composition of a Coating Solution for a Green Pattern)

PG36/PY150 dispersion 34 parts by weight

Photosensitive resin composition 66 parts by weight

Propylene glycol monomethyl ether acetate 400 parts by weight

(Composition of a Coating Solution for a Blue Pattern)

PB15:6/PV23 dispersion 17 parts by weight

Photosensitive resin composition 83 parts by weight

Propylene glycol monomethyl ether acetate 400 parts by weight

Comparative Example

A black matrix (14.4 μm, film thickness 1.1 μm) was formed in the samemariner as in the example except that the development was carried out inan ordinary condition in the above-mentioned developing process. Thewidth of the thick film region at the time was 11.5 μm, and the width ofthe thin film region was 0.7 μm. Subsequently, a color filter was formedby the same process as in the example. The difference between themaximum film thickness in the stacked part with the colored layersuperimposed on a part of the light shielding part of the formed colorfilter and the film thickness of the central part of the colored layerformed in the opening part of the light shielding part was 0.7 μm.

[Evaluation]

In the case of using a color filter of the example, a liquid crystaldisplay apparatus having a preferable display characteristic can beobtained. On the other hand, in the case of using a color filter of thecomparative example, alignment defect was generated in a part thereof.

1. A method for producing a color filter comprising the steps of:preparing a light shielding part forming composition containing at leasta light shielding material and a resin; forming a light shielding parton a transparent substrate by using the light shielding part formingcomposition; and forming a colored layer in an opening part of the lightshielding part, wherein the step of forming a light shielding partfurther comprises a process of pouring the light shielding part formingcomposition into a mold having a shape for forming the light shieldingpart of the following shape, curing and attaching the light shieldingpart onto the transparent substrate: a width of a thick film region, 85%or more of a maximum film thickness of the light shielding part anddisposed in a central part of the light shielding part, is in a range of30% to 60% of a light shielding part linear width; and a width of eachof thin film regions, 50% or less of the maximum film thickness of thelight shielding part and disposed on both side parts of the lightshielding part, is in a range of 10% to 20% of the light shielding partlinear width.
 2. A method for producing a color filter comprising thesteps of: preparing a light shielding part forming compositioncontaining at least a light shielding material and a resin; forming alight shielding part on a transparent substrate by using the lightshielding part forming composition; and forming a colored layer in anopening part of the light shielding part, wherein the step of forming alight shielding part further comprises a process of coating the lightshielding part forming composition onto the transparent substrate, usinga half tone mask to change an exposing amount to the light shieldingpart forming composition and forming a shape of the light shielding partas follows: a width of a thick film region, 85% or more of a maximumfilm thickness of the light shielding part and disposed in a centralpart of the light shielding part, is in a range of 30% to 60% of a lightshielding part linear width; and a width of each of thin film regions,50% or less of the maximum film thickness of the light shielding partand disposed on both side parts of the light shielding part, is in arange of 10% to 20% of the light shielding part linear width.
 3. Themethod for producing a color filter according to claim 1, wherein,during the step of forming a colored layer, the colored layer is formedso as to cover a part of the light shielding part, and such that adifference between a maximum film thickness of a superimposed part withthe colored layer superimposed on the part of the light shielding partand a film thickness of a central part of the colored layer formed inthe opening part of the light shielding part is 0.5 μm or less.
 4. Themethod for producing a color filter according to claim 2, wherein,during the step of forming a colored layer, the colored layer is formedso as to cover a part of the light shielding part, and such that adifference between a maximum film thickness of a superimposed part withthe colored layer superimposed on the part of the light shielding partand a film thickness of a central part of the colored layer formed inthe opening part of the light shielding part is 0.5 μm or less.
 5. Themethod for producing a color filter according to claim 1, wherein,during the step of forming a colored layer, the colored layer is formed:so as to cover a part of the light shielding part; and so as that thecolored layer has a crossing part with the colored layer and the lightshielding part crossing each other such that the colored layer coversthe light shielding part, and a difference between a maximum filmthickness of the crossing part and a film thickness of a central part ofthe colored layer formed in the opening part of the light shielding partis 0.5 μm or less.
 6. The method for producing a color filter accordingto claim 2, wherein, during the step of forming a colored layer, thecolored layer is formed: so as to cover a part of the light shieldingpart; and so as that the colored layer has a crossing part with thecolored layer and the light shielding part crossing each other such thatthe colored layer covers the light shielding part, and a differencebetween a maximum film thickness of the crossing part and a filmthickness of a central part of the colored layer formed in the openingpart of the light shielding part is 0.5 μm or less.